1. Technical Field
The disclosure relates to a lens structure. More particularly, the disclosure relates to an optical coupling element and an optical module having the same.
2. Background
There are two ways for the photoelectrical transmission. One is to couple beams emitted from a laser transmitter to an optical fiber by turning their optical paths 90 degrees by a 45-degree total reflection surface. The other way is to transmit the beams horizontally without turning the optical paths, in order to couple lens arrays to the optical fiber.
With the 45-degree total reflection surface, reflections and focal lengths may be controlled easily in the photoelectrical transmission. Additionally, the transmission efficiency of the photoelectrical transmission may also be improved. Thus, a user usually couples the beams emitted from the laser transmitter to the optical fiber by the 45-degree total reflection surface.
However, because the materials of the optical fiber do not suit to the photoelectrical transmission and the beams are perpendicular to optical coupling surface of the optical fiber, parts of the beams emitted from the laser transmitter may be reflected back to the laser transmitter by the optical coupling surface. Moreover, optical interferences may occur as well, which reduces the transmission efficiency of the photoelectrical transmission. To improve the optical interferences, an 8-degree inclined plane is developed. Although the 8-degree inclined plane may be adapted to prevent the beams from being reflected back to the laser transmitter by the optical coupling surface, the optical coupling effects of the optical fiber may be significantly decreased. Thus, it is important to improve the optical coupling effects and the optical interferences in the photoelectrical transmission in this field.